staging: vt6655:fix warning for unexported non-static functions

There is one function in aes_ccmp.c which is exported, but sparse sees
it unexported because it doesn't include the header that exports it.

Signed-off-by: Guillaume Clement <gclement@baobob.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>